Oil flow control for dry sump pumps



july Mw i953 R., L. D|| s 2,645,102

- om FLOW CONTROL. Foa DRY sumD PUMPS Filed sept. 2o, 1951 Ihvehtcr: Raymond L. D i IS,

by His Attorney.

Patented July 14, 1953 OIL FLOW CONTROL FOR DRY SUMP PUMPS I Raymond L. Dills, Erie, Pa., assignor to General Electric Company, a corporation of New York Application September 20, 1951, Serial No. 247,413 Claims. (Cl. 62-117.75)

My invention relates to refrigerating apparatus and pertains more particularly to an oil flow control employable between the evaporator header and the compressor of a refrigeration circuit.

In a refrigeration system of the compression type, it is not unusual for the compressed refrigerant to entrain the compressor lubricant and thus carry it through to the evaporator. This in itself is usually not harmful. However, the return of this admixture to the compressor is often in slugs and surges of vapor and liquid refrigerant and lubricant so that in periods between such surges there is insuiiicient sealing oil and, therefore, pressure fluctuation on thehigh side of the system, Accordingly, it is the primary object of my invention to provide means for returning the lubricant to the compressor in a manner effective for maintaining an eiiicient oil seal therein and thereby effecting a more constant pressure on the high side of the compressor.

Further objects and advantages of my invention will become apparent as the following description proceeds,v and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed'to and forming part of this specification.

Briefly, my invention contemplates a provision in a refrigeration circuit between the evaporator `and compressor of a device by which an admiX- ture of refrigerants and lubricant is separable into vaporous and liquid constituents, respectively, and wherefrom the lubricant is metered substantially constantly to the compressor during the operating period of the compressor. The device is positioned in a relatively warm region to facilitate vaporization of any remaining liquid refrigerant.

For a better understanding of my invention,

reference may be had to the accompanying Y drawing in which Fig. l is a side elevation view of, a refrigerator illustrating an embodiment of my invention in the refrigeration circuit thereof and Fig. 2 is a longitudinal sectional View of one construction for carrying out my invention.

Referring to Fig. 1, there is shown a refrigerator I which includes a food storage or cold-air compartment 2 anda machinery-enclosing or warm-air compartment 3. Provided for refrigerating the food storage compartment is an evaporator Il located therein. The evaporator is supplied through a capillary tube 5 with a liquid refrigerant from a condenser 6. Compression of refrigerant is effected by a refrigerating unit 'I Which is located in the warm-air compartment 3.

vair compartment and Vaporized refrigerant is Withdrawn -by the compressol1 from the evaporator through a suction line or return Yconduit 8, which conduit is connected, as better seen in Fig. 2, with a lubricant trap including a housing 9. 'I'he housing 9 is adapted for being connected in the suction line and is. further adapted for receiving and retaining or trapping a predetermined amount of lubricant. The connection to the housing 9 is effected through a top inlet passage IIJ positioned above a level normally reached by lubricant in said housing. The housing 9 is locatedin the warmis further connected through a lateral outlet passage` II with the refrigerating unit l. The lateral outlet passage is positioned a limited distance above the mentioned normal lubricant level and the mouth thereof extends into the interior of the housing.

In operation slugs of vaporous and liquid refrigerant and lubricant enter the housing through the inlet passage I0 wherein, due to the warm-air location of said housing, any remaining liquid refrigerant is Vaporized. Thus, substantially al1 of the refrigerant is caused to rise as vapor, indicated by I2 in Fig. 2, to the top portion of the housing While the oil, indicated by I3, collects in the bottom portion.

As also seen in Fig. 2, a pendent baffle I4 is provided in the housing 9. The baille I4 is spaced a limited distance laterally from the mouth of the outlet passage I I and extends from the top of said housing to a point in substantially the same plane as the lower edgeof the outlet passage.

As pointed out above, definite relationships exist between the outlet passage I I and both the normal lubricant level and the baille I4. These effect a limited spacing between the lower edge of the baiiie and the normal lubricant level whereby the vapor, as it is drawn out of the housing and to the refrigeratng unit, is directed to the surface of the oil and its velocity is increased as it passes through the restricted space between the bottom of the baffle and said oil surface. Thus, the surface of the collected oil just beneath the baffle is Washed or swept over by the vapor which results in a deliverance of oil in substantially metered amounts to the refrigerating unit through the outlet passage I I, the lower edge of which is spaced a limited distance above the normal lubricant level and substantially in the same horizontal plane as the lower edge of the baille I4. In this manner an efficient seal is maintained in the compressor and pressure fluctuations due to improper oil sealing are prevented.

In constructing a preferred form of my invention I have found that maximum efficiency was attained when the mouth of the outlet passage il extended at least 1A inside the housing 9. I spaced the pendent baille laterally between Tae and from the mouth of the outlet passage. I found the &" spacing to be the optimum position for the baille and the 378" to be the maximum permissible spacing. Optimum position for the lower edge of the baille was found to be in substantially the same plane as the lower inside surface of the outlet passage Il. This, however, was found to be variable to approximately tig above the mentioned plane.

While I have shown and described a specific embodiment of my invention, VI do not desire my invention to be limited to the particular construction shown and described and I intend by the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as lnew and desire to secure by Letters Patent of the United States is:

l. In a refrigerating system including an evaporator, a refrigerating unit and a suction line for returning lubricant and refrigerant from said evaporator to said refrigerating unit, a lubricant trap connected in said suction line, said trap being disposed in a region subjected to a temperature at least ashigh as ambient whereby evaporation of any liquid refrigerant is effected therein, said trap includinga housing having an inlet passage and a lateral outlet passage disposed above the normal level of lubricant in said housing, and a. pendent baille within said housing between said inlet passage and said outlet passage and adjacent said outlet passage, the lower end of said baille being positioned a limited distance above said normal level of lubricant in said housing whereby Vaporized refrigerant sweeping by lower end of said baille effects metering oi' lubricant into said outlet passage and to said r'efrigerating unit.

2. A refrigerator comprising a food storage compartment anda machinery compartment; a refrigerating system including an evaporator disposed inv said storage compartment for cooling said storage compartment and a refrigerating unit disposed in said machinery compartment, a suction line for returning refrigerant from said evaporator to said refrigerating unit, a lubricant trap connected .in said suction line, said trap being disposed in said machinery compartment whereby evaporation of any liquid refrigerant is effected therein, said trap including a housing having an inlet passage and a lateral outlet passage positioned a limited distance above the normal level of lubricant in said housing, a pendent baffle within said housing between said inlet passage and said outlet passage and adjacent said outlet passage, the lower end of said baffle being positioned a limited distance above said normal level of lubricant in said housing whereby vapor-ized refrigerant sweeping by the lower end of said baille effects metering of lubricant through said outlet passage and to said refrigerating unit.

3. A refrigerator comprising a food storage compartment and a machinery compartment, a refrigerating system including an evaporator disposed in said storage compartment for cooling said storage compartment, a refrigerating unit disposed in said machinery compartment, a suction line for returning refrigerant from said evaporator to said refrigerating unit, a lubricant trap connected in said suction line, said trap being disposed in said machinery compartment whereby evaporation of any liquid refrigerant is effected therein, said trap including a housing having an inlet passage *above the normal lubricant level in said housingand a lateral outlet passage positioned a limited distance above said normal lubricant level, a pendent baifle within said housing between said inlet passage and said outlet passage and spaced a limited distance from said outlet passage, the lower end of said baille being insubstantially the same plane as the lower edge of said outlet passage whereby vaporized refrigerant sweeping by said lower end `of said baille effects metering of lubricant into said outlet passage and to said refrigerating unit.

4. A device of the class described wherein an adinixture of refrigerant and lubricant is separated into a vapor and a liquid, respectively, and from which the liquid is metered during a draft of the vapor comprising; a housing, an inlet passage above the normal liquid level reached in said housing, a lateral outlet passage having the mouth thereof extending into said housing and positioned a limited distance above said normal liquid level, a baille between said inlet passage and outlet passage and spaced a limited distance from the mouth of said outlet, said bafle extending from the top of said housing to a point in substantially the same plane as the lower edge of said outlet passage whereby the vapor when drafted is directed to sweep the surface of the liquid thereby to carry substantially metered amounts thereof through said outlet passage.

5. A device of the class described wherein an adrnixture of refrigerant and lubricant is separated into a vapor and a liquid, respectively, and from which the liquid is metered during a draft of the vapor comprising; a housing, an inlet passage above the normal liquid level reached in said housing, a lateral outlet passage having the mouth thereof extending into said housing at least 1/4" and positioned a limited distance above said normal liquid level, a baille between said inlet passage and outlet passage and spaced laterally between T35 and from the mouth of said outlet, said baille extending from the top of said housing to between a point in substantially the same plane as the lower inside surface of said outlet passage and a point l/q thereabove, whereby the vapor when drafted is directed to sweep the surface of the liquid thereby to carry substantially metered amounts thereof through said outlet passage.

RAYMOND L. DILLS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name v Date 2,301,656 Hirche Nov. 10, 1942 2,512,758 Winkler June 27, 1950 

